This invention rleates to a novel method of producing a reclosable bag and the product reclosable bag which is inexpensive to manufacture and easy to use.
An increasing number of articles are packaged in plastic bags. In addition, rolls of plastic bags are presently sold for consumer use in packaging household items or the like. It is often desirable to have the ability to remove at least part of the bag's contents and reclose the bag thereafter. However, various disadvantages have been found with prior art reclosable bags.
For example, one type of reclosable bag is disclosed in Ruda U.S. Pat. No. 3,759,438. In the Ruda construction, a stiffener is located inside the mouth of the bag, which provides a construction that is relatively difficult to manufacture. In the Ruda construction, in order to heat seal the stiffener special equipment is required having an insulative device between the plies of the bag, so that the front and back plies of the bag will not become heat sealed to each other. Thus in producing Ruda's reclosable bag, it is advantageous to heat seal the stiffener prior to heat sealing the sides of the bag. At that time, the front and back plies of the bag are not adjacent each other and the stiffener may be heat sealed without heat sealing the front and back plies of the bag to each other. In any event, in manufacturing the Ruda reclosable bag at least two separate heat sealing steps are required using two different machine operations. Additionally, by using a stiffener which has a length substantially less than the width of the bag, a continuous flow operation is difficult. In such cases, an intermittent break off is required, thereby preventing a continuous operation.
The prior art patent to White, U.S. Pat. No. 3,889,871, discloses another type of reclosable bag in which a separate tape is required to connect the stiffener to the bag. The requirement of a separate fastening means is deleterious to optimum manufacture.
Another type of alleged reclosable bag construction is disclosed in Hoeppner, et al. U.S. Pat. No. 2,620,842, in which a flap overlies the front wall and mouth of the bag, to provide a handle and closure means. However, the security of the Hoeppner, et al. bag is questionable because there is no tie or stiffener to provide a repeatable secure closure.
The prior art patents to Rivman, et al. U.S. Pat. No. 3,321,126 and Chesney U.S. Pat. No. 587,928 show other prior art reclosable containers. In the Rivman, et al. patent, an external strip is required to be fastened over a wire stiffener. This has the disadvantage mentioned above in connection with White U.S. Pat. No. 3,889,871. Chesney discloses a paper container in which a stiffener is fastened below the mouth of the bag, so that the mouth of the bag becomes rolled about with the stiffener being bent to close the roll. In the Chesney construction, an external fastening strip is needed to fasten the stiffener to the bag.
It is an object of the present invention to provide a plastic bag that overcomes many of the disadvantages of prior art plastic bags, and a novel process which produces such plastic bags in an extremely efficient and relatively inexpensive manner.
Another object of the present invention is to provide a novel process for producing a reclosable plastic bag of a type which does not require external fastening means.
A further object of the present invention is to provide a plastic bag construction in which the bag is heat sealed to contain a stiffener, with the heat sealing being accomplished in an efficient manner.
Another object of the present invention is to provide a process for producing a reclosable plastic bag using a continuous closure strip, thereby obviating the necessity for an intermittent break off.
Other objects and advantages of the present invention will become apparent as the description proceeds.